Conventional rubber materials for air spring rubber compositions for use in such applications as air suspensions for railway vehicles, a variety of industrial equipment, and automobiles (such as cars, trucks, and buses) include natural rubber, butyl rubber, and chloroprene rubber. When resistance to flex fatigue is only required, natural rubber is generally used for rubber compositions for air springs. On the other hand, when prevention of ozone-induced cracking, oil resistance, or heat resistance is required, butyl rubber, chloroprene rubber, or a rubber blend of chloroprene rubber and natural rubber is used depending on the service conditions (see Patent Documents 1 and 2).
However, butyl rubber and chloroprene rubber are embrittled under a low-temperature environment, and therefore, there has been a demand for an air spring rubber composition having high versatility, weather resistance including low-temperature characteristic, resistance to flex fatigue, and ozone resistance.    Patent Document 1: JP-A-11-82739    Patent Document 2: JP-A-2008-132641